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WA dad guilty over teen's insulin overdose

Cher Deliu will need constant care for the rest of her life after she had a potentially fatal dose of insulin.

She is fed and breathes through tubes and remains unresponsive, so we will never know how and why she ingested the insulin, but it is possible she did it to herself.

But on Tuesday, a West Australian District Court jury found her diabetic father, James Chad Deliu, guilty of causing aggravated grievous bodily harm by failing to seek medical treatment for the 18-year-old over two days in March last year.

Cher's half-sister Susan Deliu testified that she visited the pair at home and was told to leave Cher alone because she had been drinking alcohol and had then taken some sleeping pills.

But hours later, Ms Deliu found Cher lying unresponsive on a mattress.

When Ms Deliu suggested Cher should be taken to hospital, her father replied: "No, I'll get charged. I'll go to jail".

He eventually agreed to take Cher to a hospital after he brought Ms Deliu home, but instead, he drove Cher to his brother's house, about 100km away, and plied her with sugar, the court heard.

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Cher's stepbrother Jeffrey Brugman found Cher unresponsive when he visited the house the next day and took her to hospital.

Mr Brugman testified that he lied to police in three statements because he did not want to "damage" Deliu, and only told them what really happened a week before the trial began because Deliu did not come clean.

It took more than five hours for the jury to reach their decision after hearing about two weeks of evidence, and some family members cried when the verdict was handed down.

Judge Julie Wager told Deliu he had been convicted of a very serious charge.

"It has had significant repercussions, particularly for your daughter Cher," she said.

A pre-sentence report and psychological report were ordered for a sentencing hearing on October 22.